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Arbanasić H, Medrano-González L, Hrenar T, Mikelić A, Gomerčić T, Svetličić I, Pavlinec Ž, Đuras M, Galov A. Recent selection created distinctive variability patterns on MHC class II loci in three dolphin species from the Mediterranean Sea. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2024; 150:105079. [PMID: 37832898 DOI: 10.1016/j.dci.2023.105079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 10/10/2023] [Accepted: 10/10/2023] [Indexed: 10/15/2023]
Abstract
The major histocompatibility complex (MHC) includes highly polymorphic genes involved in antigen presentation, which is crucial for adaptive immune response. They represent fitness related genetic markers particularly informative for populations exposed to environmental challenges. Here we analyse the diversity and evolutionary traits of MHC class II DQA and DQB genes in the dolphins Stenella coeruleoalba and Grampus griseus from the Mediterranean Sea. We found substantial nucleotide and functional diversity, as well as strong evidence of balancing selection indicated by allele and supertype frequencies, Tajima's D statistics and dN/dS tests. The Risso's dolphin, considered the least abundant in the region, showed the effect of divergent allele advantage at the nucleotide and functional-peptide levels. An outstanding polymorphism was found in the striped dolphin, particularly intriguing in the DQA gene where the Ewens-Watterson test detected a selection sweep that occurred in recent history. We hypothesize that morbillivirus, which has recurrently invaded Mediterranean populations over the last decades, exerted the detected selective pressure.
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Affiliation(s)
- Haidi Arbanasić
- Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000, Zagreb, Croatia.
| | - Luis Medrano-González
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico.
| | - Tomica Hrenar
- Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000, Zagreb, Croatia.
| | - Ana Mikelić
- Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000, Zagreb, Croatia.
| | - Tomislav Gomerčić
- Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000, Zagreb, Croatia.
| | - Ida Svetličić
- Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000, Zagreb, Croatia.
| | - Željko Pavlinec
- Croatian Academy of Sciences and Arts, Trg Nikole Šubića Zrinskog 11, 10000, Zagreb, Croatia.
| | - Martina Đuras
- Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000, Zagreb, Croatia.
| | - Ana Galov
- Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000, Zagreb, Croatia.
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2
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Eltschkner S, Mellinger S, Buus S, Nielsen M, Paulsson KM, Lindkvist-Petersson K, Westerdahl H. The structure of songbird MHC class I reveals antigen binding that is flexible at the N-terminus and static at the C-terminus. Front Immunol 2023; 14:1209059. [PMID: 37483599 PMCID: PMC10360169 DOI: 10.3389/fimmu.2023.1209059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/08/2023] [Indexed: 07/25/2023] Open
Abstract
Long-distance migratory animals such as birds and bats have evolved to withstand selection imposed by pathogens across the globe, and pathogen richness is known to be particularly high in tropical regions. Immune genes, so-called Major Histocompatibility Complex (MHC) genes, are highly duplicated in songbirds compared to other vertebrates, and this high MHC diversity has been hypothesised to result in a unique adaptive immunity. To understand the rationale behind the evolution of the high MHC genetic diversity in songbirds, we determined the structural properties of an MHC class I protein, Acar3, from a long-distance migratory songbird, the great reed warbler Acrocephalus arundinaceus (in short: Acar). The structure of Acar3 was studied in complex with pathogen-derived antigens and shows an overall antigen presentation similar to human MHC class I. However, the peptides bound to Acar3 display an unusual conformation: Whereas the N-terminal ends of the peptides display enhanced flexibility, the conformation of their C-terminal halves is rather static. This uncommon peptide-binding mode in Acar3 is facilitated by a central Arg residue within the peptide-binding groove that fixes the backbone of the peptide at its central position, and potentially permits successful interactions between MHC class I and innate immune receptors. Our study highlights the importance of investigating the immune system of wild animals, such as birds and bats, to uncover unique immune mechanisms which may neither exist in humans nor in model organisms.
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Affiliation(s)
- Sandra Eltschkner
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden
| | - Samantha Mellinger
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden
| | - Soren Buus
- Department of Experimental Immunology, Institute of International Health, Immunology and Microbiology, Copenhagen, Denmark
| | - Morten Nielsen
- Immunoinformatics and Machine Learning, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark
| | - Kajsa M. Paulsson
- Antigen Presentation, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Karin Lindkvist-Petersson
- Medical Structural Biology, Department of Experimental Medical Science, Lund University, Lund, Sweden
- LINXS - Institute of Advanced Neutron and X-ray Science, Lund University, Lund, Sweden
| | - Helena Westerdahl
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden
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3
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Vinkler M, Fiddaman SR, Těšický M, O'Connor EA, Savage AE, Lenz TL, Smith AL, Kaufman J, Bolnick DI, Davies CS, Dedić N, Flies AS, Samblás MMG, Henschen AE, Novák K, Palomar G, Raven N, Samaké K, Slade J, Veetil NK, Voukali E, Höglund J, Richardson DS, Westerdahl H. Understanding the evolution of immune genes in jawed vertebrates. J Evol Biol 2023; 36:847-873. [PMID: 37255207 PMCID: PMC10247546 DOI: 10.1111/jeb.14181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 04/23/2023] [Accepted: 04/26/2023] [Indexed: 06/01/2023]
Abstract
Driven by co-evolution with pathogens, host immunity continuously adapts to optimize defence against pathogens within a given environment. Recent advances in genetics, genomics and transcriptomics have enabled a more detailed investigation into how immunogenetic variation shapes the diversity of immune responses seen across domestic and wild animal species. However, a deeper understanding of the diverse molecular mechanisms that shape immunity within and among species is still needed to gain insight into-and generate evolutionary hypotheses on-the ultimate drivers of immunological differences. Here, we discuss current advances in our understanding of molecular evolution underpinning jawed vertebrate immunity. First, we introduce the immunome concept, a framework for characterizing genes involved in immune defence from a comparative perspective, then we outline how immune genes of interest can be identified. Second, we focus on how different selection modes are observed acting across groups of immune genes and propose hypotheses to explain these differences. We then provide an overview of the approaches used so far to study the evolutionary heterogeneity of immune genes on macro and microevolutionary scales. Finally, we discuss some of the current evidence as to how specific pathogens affect the evolution of different groups of immune genes. This review results from the collective discussion on the current key challenges in evolutionary immunology conducted at the ESEB 2021 Online Satellite Symposium: Molecular evolution of the vertebrate immune system, from the lab to natural populations.
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Affiliation(s)
- Michal Vinkler
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | | | - Martin Těšický
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | | | - Anna E. Savage
- Department of BiologyUniversity of Central FloridaFloridaOrlandoUSA
| | - Tobias L. Lenz
- Research Unit for Evolutionary ImmunogenomicsDepartment of BiologyUniversity of HamburgHamburgGermany
| | | | - Jim Kaufman
- Institute for Immunology and Infection ResearchUniversity of EdinburghEdinburghUK
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - Daniel I. Bolnick
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsConnecticutUSA
| | | | - Neira Dedić
- Department of Botany and ZoologyMasaryk UniversityBrnoCzech Republic
| | - Andrew S. Flies
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmaniaAustralia
| | - M. Mercedes Gómez Samblás
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
- Department of ParasitologyUniversity of GranadaGranadaSpain
| | | | - Karel Novák
- Department of Genetics and BreedingInstitute of Animal SciencePragueUhříněvesCzech Republic
| | - Gemma Palomar
- Faculty of BiologyInstitute of Environmental SciencesJagiellonian UniversityKrakówPoland
| | - Nynke Raven
- Department of ScienceEngineering and Build EnvironmentDeakin UniversityVictoriaWaurn PondsAustralia
| | - Kalifa Samaké
- Department of Genetics and MicrobiologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | - Joel Slade
- Department of BiologyCalifornia State UniversityFresnoCaliforniaUSA
| | | | - Eleni Voukali
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | - Jacob Höglund
- Department of Ecology and GeneticsUppsala UniversitetUppsalaSweden
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4
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O'Connor EA, Westerdahl H, Burri R, Edwards SV. Avian MHC Evolution in the Era of Genomics: Phase 1.0. Cells 2019; 8:E1152. [PMID: 31561531 PMCID: PMC6829271 DOI: 10.3390/cells8101152] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/16/2019] [Accepted: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
Birds are a wonderfully diverse and accessible clade with an exceptional range of ecologies and behaviors, making the study of the avian major histocompatibility complex (MHC) of great interest. In the last 20 years, particularly with the advent of high-throughput sequencing, the avian MHC has been explored in great depth in several dimensions: its ability to explain ecological patterns in nature, such as mating preferences; its correlation with parasite resistance; and its structural evolution across the avian tree of life. Here, we review the latest pulse of avian MHC studies spurred by high-throughput sequencing. Despite high-throughput approaches to MHC studies, substantial areas remain in need of improvement with regard to our understanding of MHC structure, diversity, and evolution. Recent studies of the avian MHC have nonetheless revealed intriguing connections between MHC structure and life history traits, and highlight the advantages of long-term ecological studies for understanding the patterns of MHC variation in the wild. Given the exceptional diversity of birds, their accessibility, and the ease of sequencing their genomes, studies of avian MHC promise to improve our understanding of the many dimensions and consequences of MHC variation in nature. However, significant improvements in assembling complete MHC regions with long-read sequencing will be required for truly transformative studies.
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Affiliation(s)
| | | | - Reto Burri
- Department of Population Ecology, Institute of Ecology & Evolution, Friedrich Schiller University Jena, 07737 Jena, Germany.
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA.
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5
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Králová T, Albrecht T, Bryja J, Hořák D, Johnsen A, Lifjeld JT, Novotný M, Sedláček O, Velová H, Vinkler M. Signatures of diversifying selection and convergence acting on passerine Toll-like receptor 4 in an evolutionary context. Mol Ecol 2018; 27:2871-2883. [PMID: 29772096 DOI: 10.1111/mec.14724] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 04/23/2018] [Accepted: 04/24/2018] [Indexed: 12/26/2022]
Abstract
Positive selection acting on Toll-like receptors (TLRs) has been recently investigated to reveal evolutionary mechanisms of host-pathogen molecular co-adaptation. Much of this research, however, has focused mainly on the identification of sites predicted to be under positive selection, bringing little insight into the functional differences and similarities among species and a limited understanding of convergent evolution in the innate immune molecules. In this study, we provide evidence of phenotypic variability in the avian TLR4 ligand-binding region (LBR), the direct interface between host and pathogen molecular structures. We show that 55 passerine species vary substantially in the distribution of electrostatic potential on the surface of the receptor, and based on these distinct patterns, we identified four species clusters. Seven of the 34 evolutionarily nonconservative and positively selected residues correspond topologically to sites previously identified as being important for lipopolysaccharide, lipid IVa or MD-2 binding. Five of these positions codetermine the identity of the charge clusters. Groups of species that host-related communities of pathogens were predicted to cluster based on their TLR4 LBR charge. Despite some evidence for convergence among taxa, there were no clear associations between the TLR4 LBR charge distribution and any of the general ecological characteristics compared (migration, latitudinal distribution and diet). Closely related species, however, mostly belonged to the same surface charge cluster indicating that phylogenetic constraints are key determinants shaping TLR4 adaptive evolution. Our results suggest that host innate immune evolution is consistent with Fahrenholz's rule on the cospeciation of hosts and their parasites.
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Affiliation(s)
- Tereza Králová
- Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tomáš Albrecht
- Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic.,Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Josef Bryja
- Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - David Hořák
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Arild Johnsen
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Jan T Lifjeld
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Marian Novotný
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Ondřej Sedláček
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Hana Velová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michal Vinkler
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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6
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Minias P, Pikus E, Whittingham LA, Dunn PO. A global analysis of selection at the avian MHC. Evolution 2018; 72:1278-1293. [PMID: 29665025 DOI: 10.1111/evo.13490] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/29/2018] [Accepted: 04/09/2018] [Indexed: 12/29/2022]
Abstract
Recent advancements in sequencing technology have resulted in rapid progress in the study of the major histocompatibility complex (MHC) in non-model avian species. Here, we analyze a global dataset of avian MHC class I and class II sequences (ca. 11,000 sequences from over 250 species) to gain insight into the processes that govern macroevolution of MHC genes in birds. Analysis of substitution rates revealed striking differences in the patterns of diversifying selection between passerine and non-passerine birds. Non-passerines showed stronger selection at MHC class II, which is primarily involved in recognition of extracellular pathogens, while passerines showed stronger selection at MHC class I, which is involved in recognition of intracellular pathogens. Positions of positively selected amino-acid residues showed marked discrepancies with peptide-binding residues (PBRs) of human MHC molecules, suggesting that using a human classification of PBRs to assess selection patterns at the avian MHC may be unjustified. Finally, our analysis provided evidence that indel mutations can make a substantial contribution to adaptive variation at the avian MHC.
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Affiliation(s)
- Piotr Minias
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, 90-237, Poland
| | - Ewa Pikus
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, 90-237, Poland
| | - Linda A Whittingham
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53211
| | - Peter O Dunn
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, 90-237, Poland.,Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53211
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7
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Biedrzycka A, O'Connor E, Sebastian A, Migalska M, Radwan J, Zając T, Bielański W, Solarz W, Ćmiel A, Westerdahl H. Extreme MHC class I diversity in the sedge warbler (Acrocephalus schoenobaenus); selection patterns and allelic divergence suggest that different genes have different functions. BMC Evol Biol 2017; 17:159. [PMID: 28679358 PMCID: PMC5497381 DOI: 10.1186/s12862-017-0997-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 06/14/2017] [Indexed: 11/23/2022] Open
Abstract
Background Recent work suggests that gene duplications may play an important role in the evolution of immunity genes. Passerine birds, and in particular Sylvioidea warblers, have highly duplicated major histocompatibility complex (MHC) genes, which are key in immunity, compared to other vertebrates. However, reasons for this high MHC gene copy number are yet unclear. High-throughput sequencing (HTS) allows MHC genotyping even in individuals with extremely duplicated genes. This HTS data can reveal evidence of selection, which may help to unravel the putative functions of different gene copies, i.e. neofunctionalization. We performed exhaustive genotyping of MHC class I in a Sylvioidea warbler, the sedge warbler, Acrocephalus schoenobaenus, using the Illumina MiSeq technique on individuals from a wild study population. Results The MHC diversity in 863 genotyped individuals by far exceeds that of any other bird species described to date. A single individual could carry up to 65 different alleles, a large proportion of which are expressed (transcribed). The MHC alleles were of three different lengths differing in evidence of selection, diversity and divergence within our study population. Alleles without any deletions and alleles containing a 6 bp deletion showed characteristics of classical MHC genes, with evidence of multiple sites subject to positive selection and high sequence divergence. In contrast, alleles containing a 3 bp deletion had no sites subject to positive selection and had low divergence. Conclusions Our results suggest that sedge warbler MHC alleles that either have no deletion, or contain a 6 bp deletion, encode classical antigen presenting MHC molecules. In contrast, MHC alleles containing a 3 bp deletion may encode molecules with a different function. This study demonstrates that highly duplicated MHC genes can be characterised with HTS and that selection patterns can be useful for revealing neofunctionalization. Importantly, our results highlight the need to consider the putative function of different MHC genes in future studies of MHC in relation to disease resistance and fitness. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0997-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aleksandra Biedrzycka
- Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120, Kraków, Poland.
| | - Emily O'Connor
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Ecology Building, Sölvegatan 37, 223 62, Lund, Sweden
| | - Alvaro Sebastian
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University in Poznań, ul. Umultowska 89, 61-614, Poznań, Poland
| | - Magdalena Migalska
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University in Poznań, ul. Umultowska 89, 61-614, Poznań, Poland
| | - Jacek Radwan
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University in Poznań, ul. Umultowska 89, 61-614, Poznań, Poland
| | - Tadeusz Zając
- Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120, Kraków, Poland
| | - Wojciech Bielański
- Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120, Kraków, Poland
| | - Wojciech Solarz
- Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120, Kraków, Poland
| | - Adam Ćmiel
- Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120, Kraków, Poland
| | - Helena Westerdahl
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Ecology Building, Sölvegatan 37, 223 62, Lund, Sweden
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8
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Pandya M, Rasmussen M, Hansen A, Nielsen M, Buus S, Golde W, Barlow J. A modern approach for epitope prediction: identification of foot-and-mouth disease virus peptides binding bovine leukocyte antigen (BoLA) class I molecules. Immunogenetics 2016; 67:691-703. [PMID: 26496773 DOI: 10.1007/s00251-015-0877-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/07/2015] [Indexed: 01/20/2023]
Abstract
Major histocompatibility complex (MHC) class Imolecules regulate adaptive immune responses through the presentation of antigenic peptides to CD8+ T cells. Polymorphisms in the peptide binding region of class I molecules determine peptide binding affinity and stability during antigen presentation, and different antigen peptide motifs are associated with specific genetic sequences of class I molecules. Understanding bovine leukocyte antigen (BoLA), peptide-MHC class I binding specificities may facilitate development of vaccines or reagents for quantifying the adaptive immune response to intracellular pathogens, such as foot-and-mouth disease virus (FMDV). Six synthetic BoLA class I (BoLA-I) molecules were produced, and the peptide binding motif was generated for five of the six molecules using a combined approach of positional scanning combinatorial peptide libraries (PSCPLs) and neural network-based predictions (NetMHCpan). The updated NetMHCpan server was used to predict BoLA-I binding peptides within the P1 structural polyprotein sequence of FMDV (strain A24 Cruzeiro) for Bo-LA-1*01901, BoLA-2*00801, BoLA-2*01201, and BoLA-4*02401. Peptide binding affinity and stability were determined for these BoLA-I molecules using the luminescent oxygen channeling immunoassay (LOCI) and scintillation proximity assay (SPA). The functional diversity of known BoLA alleles was predicted using theMHCcluster tool, and functional predictions for peptide motifs were compared to observed data from this and prior studies. The results of these analyses showed that BoLA alleles cluster into three distinct groups with the potential to define BBoLA supertypes.^ This streamlined approach identifies potential T cell epitopes from pathogens, such as FMDV, and provides insight into T cell immunity following infection or vaccination.
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9
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O'Connor EA, Strandh M, Hasselquist D, Nilsson JÅ, Westerdahl H. The evolution of highly variable immunity genes across a passerine bird radiation. Mol Ecol 2016; 25:977-89. [DOI: 10.1111/mec.13530] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 11/24/2015] [Accepted: 12/09/2015] [Indexed: 11/29/2022]
Affiliation(s)
- E. A. O'Connor
- Molecular Ecology and Evolution Lab; Lund University; Ecology building 223 62 Lund Sweden
| | - M. Strandh
- Molecular Ecology and Evolution Lab; Lund University; Ecology building 223 62 Lund Sweden
| | - D. Hasselquist
- Molecular Ecology and Evolution Lab; Lund University; Ecology building 223 62 Lund Sweden
| | - J.-Å. Nilsson
- Molecular Ecology and Evolution Lab; Lund University; Ecology building 223 62 Lund Sweden
| | - H. Westerdahl
- Molecular Ecology and Evolution Lab; Lund University; Ecology building 223 62 Lund Sweden
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10
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Lyons AC, Hoostal MJ, Bouzat JL. Characterization of major histocompatibility complex class I loci of the lark sparrow (Chondestes grammacus) and insights into avian MHC evolution. Genetica 2015; 143:521-34. [PMID: 26071093 DOI: 10.1007/s10709-015-9850-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 06/06/2015] [Indexed: 11/29/2022]
Abstract
The major histocompatibilty complex (MHC) has become increasingly important in the study of the immunocapabilities of non-model vertebrates due to its direct involvement in the immune response. The characterization of MHC class I loci in the lark sparrow (Chondestes grammacus) revealed multiple MHC class I loci with elevated genetic diversity at exon 3, evidence of differential selection between the peptide binding region (PBR) and non-PBR, and the presence of multiple pseudogenes with limited divergence. The minimum number of functional MHC class I loci was estimated at four. Sequence analysis revealed d N /d S ratios significantly less than one at non-PBR sites, indicative of negative selection, whereas PBR sites associated with antigen recognition showed ratios greater than 1 but non-significant. GenBank surveys and phylogenetic analyses of previously reported avian MHC class I sequences revealed variable signatures of evolutionary processes acting upon this gene family, including gene duplication and potential concerted evolution. An increase in the number of class I loci across species coincided with an increase in pseudogene prevalence, revealing the importance of gene duplication in the expansion of multigene families and the creation of pseudogenes.
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Affiliation(s)
- Amanda C Lyons
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA
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11
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Hansen AM, Rasmussen M, Svitek N, Harndahl M, Golde WT, Barlow J, Nene V, Buus S, Nielsen M. Characterization of binding specificities of bovine leucocyte class I molecules: impacts for rational epitope discovery. Immunogenetics 2014; 66:705-18. [PMID: 25186069 PMCID: PMC4225172 DOI: 10.1007/s00251-014-0802-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/25/2014] [Indexed: 10/24/2022]
Abstract
The binding of peptides to classical major histocompatibility complex (MHC) class I proteins is the single most selective step in antigen presentation. However, the peptide-binding specificity of cattle MHC (bovine leucocyte antigen, BoLA) class I (BoLA-I) molecules remains poorly characterized. Here, we demonstrate how a combination of high-throughput assays using positional scanning combinatorial peptide libraries, peptide dissociation, and peptide-binding affinity binding measurements can be combined with bioinformatics to effectively characterize the functionality of BoLA-I molecules. Using this strategy, we characterized eight BoLA-I molecules, and found the peptide specificity to resemble that of human MHC-I molecules with primary anchors most often at P2 and P9, and occasional auxiliary P1/P3/P5/P6 anchors. We analyzed nine reported CTL epitopes from Theileria parva, and in eight cases, stable and high affinity binding was confirmed. A set of peptides were tested for binding affinity to the eight BoLA proteins and used to refine the predictors of peptide-MHC binding NetMHC and NetMHCpan. The inclusion of BoLA-specific peptide-binding data led to a significant improvement in prediction accuracy for reported T. parva CTL epitopes. For reported CTL epitopes with weak or no predicted binding, these refined prediction methods suggested presence of nested minimal epitopes with high-predicted binding affinity. The enhanced affinity of the alternative peptides was in all cases confirmed experimentally. This study demonstrates how biochemical high-throughput assays combined with immunoinformatics can be used to characterize the peptide-binding motifs of BoLA-I molecules, boosting performance of MHC peptide-binding prediction methods, and empowering rational epitope discovery in cattle.
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Affiliation(s)
- Andreas M. Hansen
- Laboratory of Experimental Immunology, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Rasmussen
- Laboratory of Experimental Immunology, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicholas Svitek
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Mikkel Harndahl
- Laboratory of Experimental Immunology, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - William T. Golde
- Plum Island Animal Disease Center, Agricultural Research Service, USDA, Greenport, NY, USA
| | - John Barlow
- Department of Animal Sciences, University of Vermont, Burlington, VT, USA
| | - Vishvanath Nene
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Søren Buus
- Laboratory of Experimental Immunology, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Nielsen
- Center for Biological Sequence Analysis, Technical University of Denmark, Kongens Lyngby, Denmark,
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
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Characteristics of MHC class I genes in house sparrows Passer domesticus as revealed by long cDNA transcripts and amplicon sequencing. J Mol Evol 2013; 77:8-21. [PMID: 23877344 DOI: 10.1007/s00239-013-9575-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
In birds the major histocompatibility complex (MHC) organization differs both among and within orders; chickens Gallus gallus of the order Galliformes have a simple arrangement, while many songbirds of the order Passeriformes have a more complex arrangement with larger numbers of MHC class I and II genes. Chicken MHC genes are found at two independent loci, classical MHC-B and non-classical MHC-Y, whereas non-classical MHC genes are yet to be verified in passerines. Here we characterize MHC class I transcripts (α1 to α3 domain) and perform amplicon sequencing using a next-generation sequencing technique on exon 3 from house sparrow Passer domesticus (a passerine) families. Then we use phylogenetic, selection, and segregation analyses to gain a better understanding of the MHC class I organization. Trees based on the α1 and α2 domain revealed a distinct cluster with short terminal branches for transcripts with a 6-bp deletion. Interestingly, this cluster was not seen in the tree based on the α3 domain. 21 exon 3 sequences were verified in a single individual and the average numbers within an individual were nine and five for sequences with and without a 6-bp deletion, respectively. All individuals had exon 3 sequences with and without a 6-bp deletion. The sequences with a 6-bp deletion have many characteristics in common with non-classical MHC, e.g., highly conserved amino acid positions were substituted compared with the other alleles, low nucleotide diversity and just a single site was subject to positive selection. However, these alleles also have characteristics that suggest they could be classical, e.g., complete linkage and absence of a distinct cluster in a tree based on the α3 domain. Thus, we cannot determine for certain whether or not the alleles with a 6-bp deletion are non-classical based on our present data. Further analyses on segregation patterns of these alleles in combination with dating the 6-bp deletion through MHC characterization across the genus Passer may solve this matter in the future.
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